Method of producing polymeric phenazonium compounds

Abstract

A process of making a polymeric phenazonium compound having the general formula: wherein R1, R2, R4, R5, R6, R8, and R9 are the same or different, and represent hydrogen, a low alkyl or a substituted aryl, R3 starts with NH2 and is diazotized followed by a polymerization, R5 and R8 may alternatively represent monomeric or polymeric phenazonium radicals, R7 is a carbon in the aromatic ring, Rx and Ry represent any combination of CH3, C2H5, and hydrogen, except that Rx and Ry cannot both be hydrogen, A is an acid radical, and n is an integer from 2 to 100, preferably from 2 to 20 is described. The polymeric phenazonium compound is usable as an additive in a metal plating bath comprising copper. The method includes the steps of a) dissolving an effective amount of an amino compound in a formic acid solution; b) adding a nitrite salt to diazotize the amino compound; and c) adding sulfamic acid to neutralize any excess nitrous acid that may be formed in step b), whereby a polymeric phenazonium compound is produced with a smaller quantity of unreacted monomer remaining in the end product than those produced using methods of the prior art.

Dependencies are inferred from the claim text.